June 16, 2011

Study Finds Respimat Inhaler Increases Risk Of Death

According to new study, Respimat, a mist inhaler that delivers a widely-prescribed respiratory drug, increases the risk of dying by half.

The British and U.S. researchers looked at five trials involving Respimat, which can be alternatively taken in powder form.

The drug Respimat uses tiotropium bromide, which relaxes muscles in the airways. It is designed to ease symptoms of chronic obstructive respiratory disease (COPD), the world's fourth leading cause of death.

The study was an overview of five trials in which patients used Respimat, breathing in either tiotropium bromide, or its commercial name "Spiriva", or a placebo.

About 6,522 patients were enrolled, 3,686 of whom used the drug and 2,836 used the lookalike. Two trials lasted 12 weeks while the others were long term and lasted one year.

According to the paper published by the British Medical Journal (BMJ), the risk of death among patients using Respimat with Spiriva was 52 percent higher than the placebo group.

The risk could be cardiovascular.

Tiotropium belongs to a class of drugs known as anticholingerics, which increase the risk of heart rhythm disturbances, especially in those with a history of cardiac problems.

"What we think is going on is that the mist inhaler is delivering a higher concentration of tiotropium than it should be and that may be increasing the risk of death," Sonal Singh, an assistant professor of internal medicine at Johns Hopkins University School of Medicine and lead author of the study, said in a statement.

The study did not look at the powdered form of Spiriva, which is administered in a daily dose of 18 micrograms through a device called a HandiHaler.

Respimat delivers Spiriva as a mist in either five or 10 microgram doses. Of the 847 people who participated in the review, their risk of death was twice that of the placebo group.

According to the BMJ review, previous studies indicated that blood-level concentrations of Spiriva can be between 35 percent and 300 percent higher when compared with the 18-microgram dose from the HandiHaler.

Pfizer and Boehringer Ingelheim (BI), who both sell the inhaler, said in a statement they did not agree with the study authors' conclusion.

"When analyzing the clinical data, Boehringer Ingelheim and Pfizer, unlike the authors of the BMJ publication, have access to detailed patient level data. A thorough analysis of these data revealed a statistically non-significant, numerical imbalance in number of fatal events with Spiriva Respimat," the companies said.

The drugmakers said all the study included in the pooled analysis had been published and already shared with European regulatory authorities.

Over 55 countries have licensed the Spirivan Respimat, although the device has yet to gain regulatory approval in the U.S.

COPD kills over three million people each year, many as a result of smoking.